RibeiroAbstractObjective: To compare patients with cystic fibrosis and healthy individuals in terms of their functional performance on the six-minute walk test (6MWT). Methods: A prospective, cross-sectional study involving healthy individuals and patients with cystic fibrosis treated at a referral university hospital in the city of Campinas, Brazil. The 6MWT was administered in accordance with the American Thoracic Society guidelines, and it was repeated after a 30-min rest period. For all of the participants, RR, HR, SpO2, and Borg scale scores were obtained. For the cystic fibrosis patients, nutritional status and spirometric values were determined. Patients with pulmonary exacerbation were excluded. Spearman's correlation coefficient and repeated measures ANOVA were used. Results: The cystic fibrosis group comprised 55 patients, and the control group comprised 185 healthy individuals. The mean ages were 12.2 ± 4.3 and 11.3 ± 4.3 years, respectively. The six-minute walk distance (6MWD) was significantly shorter in the cystic fibrosis group than in the control group for both tests (547.2 ± 80.6 m vs. 610.3 ± 53.4 m for the first and 552.2 ± 82.1 m vs. 616.2 ± 58.0 m for the second; p < 0.0001 for both). The 6MWD correlated with age, weight, and height only in the cystic fibrosis group. During the tests, SpO2 remained stable, whereas HR and RR increased. Conclusions: In our sample, functional performance on the 6MWT was poorer among the cystic fibrosis patients than among the healthy controls in the same age bracket, and we found immediate repetition of the test to be unadvisable.